Post-Kala-Azar Dermal Leishmaniasis (PKDL)

Synonyms

None.

Epidemiology

Approximately 1 million new cases of cutaneous leishmaniasis worldwide per year. In South Asia (India, Nepal, Bangladesh), 5-10% of the patients with supposedly cured visceral leishmaniasis develop PKDL 2-3 years after treatment.In East Africa (Sudan, Ethiopia, Kenya and Uganda) the incidence of PKDL is higher (50-60%) and it may appear even during treatment.

Definition

Cutaneous manifestation following visceral leishmaniasis in up to 20% of patients after successful treatment.

Aetiology & Pathogenesis

PKDL lesions are due to interferon-gamma-producing cells causing skin inflammation as a reaction to persisting parasites in the skin.

Depending on the geographical region, L. donovani parasites are genetically different.

PKDL may develop through reinfection or relapse, genetic susceptibility of the host (polymorphism in the IFN-gamma receptor gene), UV-induced skin damage, organ-specific failure of memory T cell and reinfection or persistence of the parasite.

The skin lesions are a reservoir for L. donovani and promote the transmission by the female phlebotomus sandflies.

Treatment with sodium antimony gluconate (SAG) has been suggested to promote development of PKDL.

General immune response:

Asian PKDL: delayed immune response, associated with CD8+ T cell infiltration into the cutaneous lesions.
Sudanese PKDL: early reactivation of the immune response.

Signs & Symptoms

Asymptomatic skin rash, usually starting in the face, around the mouth from where it spreads to other parts of the body, presenting in 2 different versions:

Polymorphic PKDL (more common; higher burden of parasites): papulonodules (South Asia), or hypomelanotic (macular) lesions (East Africa).

Monomorphous PKDL: only one type of lesion, mostly papulonodes

Localisation

Face, spreading to other parts of the body.

Classification

Dependent on geographic region: Sudan vs India.

Laboratory & other workups

Parasitological (PCR), serological, immunological, cytological, histological biomarkers.

Dermatopathology

Polymorphic PKDL: diffuse dermial cell infiltrate with many macrophages and B cells, but fewer DCs and Langerhans cells.
Monomorphic PKDL (lower parasitic load) : reduction of Leishmania-Donovan bodies.

Course

Immune responses to PKDL in Asia and Africa are different, which may explain the better selfhealing tendency in Africa (85%) compared to the worse situation in Asia.

Complications

Persistence of the infection, relapses.

Diagnosis

Clinical sign and symptoms, along with a previous kala-azar episode and positive antibody tests.

Differential diagnosis

A variety of papulonodular and macular dermatoses.

Prevention & Therapy

PKDL lesions heal spontaneously in most cases.

Sodium antimony gluconate (SAG) (20 mg/kg per day for 20 days per month for 6 months). However, sideeffects may include cardiac toxicities and arthralgia.

Special

PKDL is not life threating, but affects the quality of life and may be a socioeconomic burden.

10.3.2 Post-Kala-Azar Dermal Leishmaniasis (PKDL)